TROPHICITY OF LACUSTRINE WATERS (LACUSTRINE WETLANDS) ON THE ROMANIAN TERRITORY

The lakes over the territory of Romania are relatively uniformly distributed in the majority of the physico-geographical regions. A low density is specific to the west, where significant draining works have been done, and the highest density is characteristic to the north-east, with numerous ponds, registered since 14-15th centuries. Most of the lakes on the Romanian territory, especially those analysed in the present study, are human made. Most of the natural lakes are small and they do not have a special ecologic or economic importance. The analysed lakes, although situated in different physico-geographical conditions, are included, in most cases, in the category of good waters from a qualitative point of view, and eutrophic, mesotrophic and hipertrophic, from a trophic point of view. As a result of the fact that most lakes are human made, it is obvious that they are maintained artificially at this stage. Most of the mountain lakes, or those in the volcanic areas, are ultra-oligotrophic and oligotrophic.